Organic light-emitting devices include a pair of electrodes and an organic compound layer disposed therebetween. When the pair of electrodes inject electrons and holes into the organic compound layer, a luminous organic compound contained therein generates excitons and emits light as they return to the ground state.
Organic light-emitting devices are also referred to as organic electroluminescent (EL) devices.
PTL 1 discloses IK-12, shown below, as an example of an organic compound constituting a light-emitting layer. This compound has benzo[k]fluoranthene, shown below, as the basic backbone thereof. Benzo[k]fluoranthene itself, that is, unsubstituted benzo[k]fluoranthene, emits light in the ultraviolet region and does not emit visible light. According to Patent Literature 1, IK-12 emits blue light as a result of substitution of the basic backbone with tert-butyl groups. IK-12 has phenyl groups at the 7- and 12-positions thereof and tert-butyl groups at the 2-, 5-, and 9-positions thereof. This inhibits concentration quenching due to molecular aggregation.

IK-12 disclosed in PTL 1 has the basic backbone thereof, namely, benzo[k]fluoranthene, substituted so that it can emit blue light. However, substituents such as tert-butyl groups may impair chemical stability.